Communicating an indicator extending an area scope of system information

ABSTRACT

A user equipment (UE) receives an indicator that extends an area scope of system information received by the UE, the system information transmitted by a wireless access network node.

BACKGROUND

A user equipment (UE) is able to connect to a mobile communicationsnetwork to perform communications. A mobile communications network ismade up of cells that correspond to respective regions in which UEs areable to establish communications with the mobile communications network.In attempting to attach to a cell, a UE monitors system information thatis broadcast by the mobile communications network, and in particular,from a wireless access network node (or multiple wireless access networknodes) of the mobile communications network. A wireless access networknode is a node of the mobile communications network that is capable ofperforming wireless communications with UEs. System information includesvarious information about the mobile communications network and cells.

System information broadcast to UEs includes messages referred to assystem information blocks (SIBs) that contain system informationelements. There can be various different types of SIBs for carryingdifferent system information.

System information also includes a master information block (MIB), whichincludes information related to other SIBs. The information relating toother SIBs contained in the MIB includes information referencing theother SIBs as well as scheduling information pertaining to the otherSIBs. A UE first reads the information elements of the MIB to allow theUE to read the information elements of the other SIBs.

In some cases, an MIB can also contain information relating to one ormore scheduling blocks (SBs), which provide references and schedulinginformation for additional SIBs (in addition to the SIBs referenced bythe MIB).

SUMMARY

In general, according to some implementations, a wireless access networknode sends, to a user equipment (UE), an indicator that extends an areascope of system information.

In general, according to further implementations, a UE includes at leastone processor to receive an indicator that extends an area scope ofsystem information received by the UE.

In general, according to other implementations, a first wireless accessnetwork entity receives, from a second wireless access network entity, asystem information configuration of the second wireless access networkentity. The first wireless access network entity identifies, based onthe received system information configuration, common system informationbetween the first and second wireless access network entities. The firstwireless access network entity sends, to a UE, an indicator extending anarea scope of the common system information.

Other or alternative features will become apparent from the followingdescription, from the drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments are described with respect to the following figures.

FIGS. 1-3 are flow diagrams of processes for sending an area scopeextending indicator by a wireless access network node to a userequipment (UE), according to some implementations.

FIG. 4 is a flow diagram of a process for sending an area scopeextending indicator between UEs, according to alternativeimplementations.

FIG. 5 is a flow diagram of tasks performed by wireless access networkentities, according to further implementations.

FIG. 6 is a block diagram of an example system including a UE and awireless access network node, according to some implementations.

DETAILED DESCRIPTION

In the ensuing discussion, reference is made to mobile communicationsnetworks that operate according to the Universal MobileTelecommunications System (UMTS) technology as provided by the ThirdGeneration Partnership Project (3GPP). UMTS technology is also referredto as the Universal Terrestrial Radio Access (UTRA) technology.

Although reference is made to UTRA in the ensuing discussion, it isnoted that techniques or mechanisms according to some implementationscan be applied to other wireless access technologies. For example, suchother wireless access technologies can include the Long-Term Evolution(LTE) technology, or another type of wireless access technology. The LTEtechnology is also referred to as the Evolved Universal TerrestrialRadio Access (E-UTRA) technology.

In a UTRA mobile communications network, system information can beorganized in a hierarchical manner, such as in the form of a tree. Forexample, the organization of system information in a tree is describedin 3GPP Technical Specification (TS) 25.331, version 11.2.0. The root ofthe tree includes the MIB, which references scheduling informationblocks (SIBs) as well as optional scheduling blocks (SBs). Each SB inturn can reference other SIBs.

Although reference is made to organizing system information of a tree insome implementations, it is noted that in other examples, systeminformation can have other types of arrangements. In a UTRA mobilecommunication network, example SIBs include SIB type 1 (also referred toas SIB1), SIB type 2 (SIB2), SIB type 3 (SIB3), and so forth. A completelisting of the SIB types can be found in 3GPP TS 25.331, in accordancewith some examples. However, it is noted that in alternativeimplementations, other types of SIBs can be employed.

The SIBs of various different types contain various differentinformation, including information that can be used by a UE to determinewhether the UE is allowed to access a cell, information relating tocells, radio resource configuration information, power controlinformation, timers, parameters for cell selection and reselection,parameters for configuration of common physical channels, and so forth.

More generally, an SIB (or system information block) refers to anymessage or information element that contains information relating to themobile communications network or one or more cells, where theinformation is usable by a UE to establish a connection to a cell of themobile communications network. More generally, reference is made tosystem information that can be read by a UE for allowing the UE toconnect to a cell of a mobile communications network. System informationcan include an SIB, an MIB, an SB, or any other type of systeminformation.

An SB provides references and scheduling information for additional SIBs(in addition to the SIBs referenced by the MIB).

Each cell can broadcast its respective system information to UEs withinthe coverage area of the respective cell. More specifically, the systeminformation broadcast in a cell is sent by the wireless access networknode of the cell. In a UTRA mobile communications network, a wirelessaccess network node includes a radio network controller (RNC) and aNodeB (NB). In some examples, the RNC carries out radio resourcemanagement and some mobility management functions. The RNC controls oneor more NodeBs, which are able to wirelessly communicate in respectivecells. A NodeB is a base transceiver station that is able to wirelesslytransmit and receive signals to and from a UE. The ensuing discussionrefers to RNCs. In other examples, techniques or mechanisms can beapplied to other types of wireless access network nodes. For example, inan E-UTRA network, the functionalities of the RNC and NodeB are includedin an enhanced NodeB (eNB).

An SIB can have one of several different area scopes. An area scope ofan SIB defines the area in which an SIB is applicable. An area scope canbe at the cell level (a “cell area scope”), in which case a UE considersthe SIB to be valid only in the cell in which the SIB was received. Inother examples, the area scope can be at the public land mobile network(PLMN) level or an equivalent PLMN level. A PLMN is a networkestablished and operated by a respective network operator. If the areascope for an SIB is the PLMN level, then a UE considers the SIB to bevalid only within the PLMN in which the SIB was received. If the areascope of an SIB is at the Equivalent PLMN level, a UE considers the SIBto be valid within the PLMN in which the SIB was received, and otherPLMN(s) indicated to be equivalent to the given PLMN.

Note also that an SB or MIB is applicable in just the cell that the SBor MIB was received.

In scenarios where the area scope of SIBs is at the cell level, it ispossible for the content of one or more SIB types to be common acrossmultiple cells. For example, the content of SIB1, SIB2, and so forth,can be common across multiple cells. Similarly, the content of an SB canbe common across multiple cells, even though traditionally the SB isapplicable in just the cell that the SB was received.

Traditionally, a UE may not be aware of the fact that certain systeminformation among neighbouring cells may be the same. As a result, whena UE reselects a new cell to camp to, the UE has to read all of thesystem information of the new cell, even though some of the systeminformation (e.g. one or more types of SIBs and one or more SBs) may becommon with the cell that the UE was previously camped on. Having toread all system information in the new cell can result in a performancepenalty at the UE, in terms of energy consumption, increased latency,increased resource usage (e.g. processor and communication componentusage), and so forth.

Solution 1

FIG. 1 is a flow diagram of an example process according to Solution 1,according to some implementations. In FIG. 1, it is assumed that the UEis initially camped on a source cell. A UE being camped on a cell refersto the UE having selected the cell (possibly from among multiplecandidate cells) to monitor for information that enables the UE toestablish a connection with the cell. The source cell (and morespecifically, an RNC of the source cell) sends (at 102) systeminformation to the UE. In accordance with some implementations, thesystem information (which can include an MIB, SIBs, and SBs) can includean indicator that extends an area scope of certain system informationsent by the source cell. This indicator can also be referred to as an“area scope extending indicator.”

For example, from the perspective of a UE, certain types of SIBs canhave a cell area scope—in other words, absent a different indicationfrom the network, the UE would interpret these SIBs to have the cellarea scope. As another example, the UE would interpret SBs to have thecell area scope.

In accordance with some implementations, the area scope extendingindicator can be provided by the network (more specifically, an RNC) toindicate to the UE that certain system information is common in anextended area, such as across multiple cells, including the source celland one or more neighbouring cells of the source cell. The area scopeextending indicator extends the area scope of the system informationfrom a first area to a larger extended area.

More specifically, according to some implementations, the area scopeextending indicator can contain information identifying whichneighbouring cell(s) and which system information (e.g. SIB type(s) orSB(s) or both) is common between the identified neighbouring cell(s) andthe source cell.

The information included in the area scope extending indicator is storedby the UE for later use.

Later, the UE selects (or reselects) (at 104) a target cell. Forexample, this target cell can be one of the neighbouring cell(s) of thesource cell identified by the area scope extending indicator to sharecertain system information with the source cell. Cell selection occurswhen the UE is initially powered up or at other times, e.g. when leavinga Radio Resource Control (RRC) Cell_DCH (Dedicated Channel State) state.RRC is described further in 3GPP TS 25.331, in some examples. Upon powerup, the UE selects one of multiple cells to camp on (see, for example,3GPP TS 25.304, version 11.0.0). Cell reselection refers to a process inwhich the UE is currently camped on a serving cell, and performsreselection of another serving cell based on one or more criteria.

The target cell (and more specifically, an RNC of the target cell) sends(at 106) system information, including an MIB, SIBs, and optionally SBs.Note that the source cell and target cell can be controlled byrespective different RNCs (source RNC and target RNC). Alternatively,the source cell and the target cell can be controlled by the same RNC.The UE uses (at 108) the information of the area scope extendingindicator (received at 102 from the source cell and stored by the UE) toread the system information transmitted by the target cell.Specifically, based on the information of area scope extendingindicator, the UE is aware of which SIB type(s) or which SB(s), or both,is (are) common between the source cell and the target cell. The UE canread and store just a subset of the system information transmitted bythe target cell, where the subset of the system information includessystem information not identified by the area scope extending indicatorto be common with system information previously received by the UE fromthe source cell.

In this manner, by reading and storing just the subset of systeminformation transmitted by the target cell, UE performance can beenhanced, since the UE does not have to waste processing, storage, andcommunication resources in reading and storing the common systeminformation (which was previously received by the UE from the sourcecell).

For the SIB type(s) identified by the area scope extending indicator tobe common between the target cell and the source cell, the UE can readthe value tag of each such common SIB type, to determine whether or notthe common SIB type should be re-read by the UE in the target cell. Thevalue tag of each common SIB type can also be included in the area scopeextending indicator.

An SIB can be labeled with a value tag that indicates the validity of astored SIB in the UE. A stored SIB that is valid can be reused by theUE. The value tag of an SIB is updated when the content of the SIB ischanged. For example, the UE may have received SIB1 having a value tagof 1. Later, when the UE determines that the value tag of SIB1 haschanged to 2, then the UE will regard the stored SIB1 as invalid, sincethe stored SIB1 is associated with value tag 1. In this case, the UEwill re-read SIB1 transmitted in a cell.

If the UE determines, based on the value tag of a particular SIB type,that the stored particular SIB type is valid (in other words, the valuetag of the particular SIB type transmitted by the target cell is thesame as the value tag of the particular SIB type stored at the UE), theUE can reuse the stored particular SIB type. However, if the value tagindicates that the particular SIB type stored at the UE is invalid, thenthe UE re-reads the particular SIB type transmitted by the target cell,even though the area scope extending indicator has indicated that theparticular SIB type is common between the target cell and the sourcecell.

In some implementations, the area scope extending indicator can beincluded in a new information element of an existing message (e.g.existing SIB type or other message) or in a new message (e.g. new SIBtype or other message). A new information element or a new messagerefers to an information element or message that is not provided bycurrent standards, but which may (or may not) be defined by futurestandards. An existing message refers to a message provided by currentstandards.

As a more specific example, the area scope extending indicator can beincluded in the Intra-frequency measurement system information of SIBtype 11 (SIB11). The Intra-frequency measurement system informationincludes an Intra-frequency cell info list information group thatcontains neighbouring cell list parameters. Further details regardingthe Intra-frequency measurement system information and theIntra-frequency cell info list information group can be found in 3GPP TS25.331.

An example of the content of the Intra-frequency measurement systeminformation of SIB11 according to 3GPP TS 25.331 is provided below. Oneof the information elements or information groups included in theIntra-frequency measurement system information is the Intra-frequencycell info list information group. The remaining information elements orinformation groups in the Intra-frequency measurement system informationare described by 3GPP TS 25.331 and will not be further discussed inthis disclosure.

Information Type and Element/Group name Need reference Intra-frequencymeasurement MD Measurement identity 10.3.7.48 identity Intra-frequencycell info list OP Intra-frequency cell info list 10.3.7.33Intra-frequency OP Intra-frequency measurement measurement quantityquantity 10.3.7.38 Intra-frequency reporting OP Intra-frequencyreporting quantity quantity for RACH for RACH Reporting 10.3.7.42Reporting Maximum number of OP Maximum number of reported cells reportedcells on RACH on RACH 10.3.7.43 Reporting information for OP Reportinginformation for state state CELL_DCH CELL_DCH 10.3.7.62

The Intra-frequency cell info list information group can be modified toadd the area scope extending indicator as a new IE, which can also bereferred to in some examples as a Common SIB info IE.

An example of the Intra-frequency cell info list information group isprovided in the table below. In the table below, the new informationelements (lEs) are underlined. The remaining IEs or information groupsof the Intra-frequency cell info list information group are explained in3GPP TS 25.331.

Information Type and Element/Group name Need Multi reference CHOICEIntra-frequency cell OP removal >Remove all intra-frequencycells >Remove some intra-frequency cells >>Removed intra-frequency cellsMP 1 to <maxCellMeas> >>>Intra-frequency cell id MP Integer(0 . . .<maxCellMeas> - 1) >Remove no intra-frequency cells New intra-frequencycells OP 1 to <maxCellMeas> >Intra-frequency cell id OP Integer(0 . . .<maxCellMeas> - 1) >Cell info MP Cell info 10.3.7.2 > Common SIB CV- 1to info BCH <maxCommSIB> >> Common SIB MP Enumerated(SIB1, indicatorSIB2, SIB5, . . .) >> Value tag MD Integer (1 . . . 4) >CHOICE modespecific info MP >>No information >>TDD 1.28 Mcps >>> SNPL Monitor SetIndicator OP Bit string(5) Cells for measurement CV- 1 to BCHopt<maxCellMeas> >Intra-frequency cell id MP Integer(0 . . .<maxCellMeas>-1) CSG Intrafrequency cell info CV- 10.3.7.121 BCHoptIntra-frequency SI Acquisition CV- 10.3.7.125 BCHoptA second format of the Intra-frequency cell info list information groupincluding a specific common SIB1 value tag is provided below.

Information Type and Element/Group name Need Multi reference CHOICEIntra-frequency cell OP removal >Remove all intra-frequencycells >Remove some intra-frequency cells >>Removed intra-frequency cellsMP 1 to <maxCellMeas> >>>Intra-frequency cell id MP Integer(0 . . .<maxCellMeas> - 1) >Remove no intra-frequency cells New intra-frequencycells OP 1 to <maxCellMeas> >Intra-frequency cell id OP Integer(0 . . .<maxCellMeas> - 1) >Cell info MP Cell info 10.3.7.2 > Common SIB CV- 1to info BCH <maxCommSIB> >> Common SIB MP Enumerated(SIB2, indicatorSIB5, . . .) >> Value tag MD Integer (1 . . . 4) >>> SIB1 Value tag OPInteger (1 . . . 256) >CHOICE mode specific info MP >>Noinformation >>TDD 1.28 Mcps >>> SNPL Monitor Set Indicator OP Bitstring(5) Cells for measurement CV- 1 to BCHopt<maxCellMeas> >Intra-frequency cell id MP Integer(0 . . .<maxCellMeas>-1) CSG Intrafrequency cell info CV- 10.3.7.121 BCHoptIntra-frequency SI Acquisition CV- 10.3.7.125 BCHopt

The new Common SIB Info IE in the table above includes a Common SIBindicator and a value tag. The Common SIB indicator identifies the SIBtype (e.g. SIB1, SIB2, etc.) that is common between the source cell andneighbouring cell(s), where the neighbouring cell(s) is (are) identifiedby part of the Cell Info IE that is included in a New intra-frequencycells information group of the table above. If there are multiple SIBtypes that are common, then the Common SIB info IE is repeated for eachsuch common SIB type, up to a maximum number (as indicated by amaxCommSIB parameter in the table above).

Similarly, if there are multiple neighbouring cells that share commonSIB information, then the Common SIB info IE would be repeated in theNew intra-frequency cells information group for each such neighbouringcell. Respective occurrences of the Cell Info IE identifies eachrespective neighbouring cell. The New intra-frequency cells informationgroup can be repeated up to a maximum number of times, as indicated by amaxCellMeas parameter in the table above.

The value tag included in the Common SIB info IE is used for indicatinga value of the value tag for the respective SIB type in the neighbouringcell, whose content is the same as the current content of thecorresponding SIB from the serving cell. The value tag is to be storedin the UE for possible later reuse.

Note that the Common SIB info IE can be in a list. The length of thelist depends upon the number of SIB types that are common, up to amaximum specified in a predefined parameter, which can be namedmaxCommSIB.

In some examples, the Common SIB info IE is conditionally present in theNew intra-frequency cells information group. More specifically, theCommon SIB info IE is present if the New intra-frequency cellsinformation group is sent in system information—otherwise, if the Newintra-frequency cells information group is not sent in systeminformation, then the Common SIB info IE is not included.

The conditional presence of the Common SIB info IE can be specified asfollows, where BCH refers to “broadcast channel.”

Condition Explanation BCHopt This IE is not needed when sent in SYSTEMINFORMATION. Otherwise, the IE is Optional BCH This IE is optional whensent in SYSTEM INFORMATION. Otherwise, the IE is not used

The foregoing examples refer to including the Common SIB info IE in theIntra-frequency measurement system information, which specifiesparameters for intra-frequency neighbouring cells (neighbouring cellsthat employ the same frequency as the source cell).

In alternative examples, the Common SIB info IE can similarly beincluded in system information for inter-frequency neighbouring cells(neighbouring cells that employ frequencies different from the frequencyof the source cell).

Although the examples described herein refer to the Common SIB info IEused to identify common SIB types, it is noted that a different IE canbe employed for identifying common SB(s) in other examples.

Alternatively, in further implementations, the Common SIB info IE can beincluded in a new SIB type (a new message, rather than an existingmessage as described above).

For example, the new SIB type can have the following format.

Information Type and Element/Group name Need Multi referenceIntra-frequency OP 1 to neighbouring cells <maxCellMeas> >CHOICE modeMP >> FDD >>>Primary CPICH info OP Primary CPICH info 10.3.6.60 >>>Common SIB MP 1 to info <maxCommSIB> >>>>Common SIB MP Enumerated(SIB1,indicator SIB2, SIB5, . . .) >>>>Value tag MD Integer (1 . . .4) >>TDD >>>Primary CCPCH info MP Primary CCPCH info 10.3.6.57 >>>Common SIB MP 1 to info <maxCommSIB> >>>>Common SIB MP Enumerated(SIB1,indicator SIB2, SIB5, . . .) >>>>Value tag MD Integer (1 . . . 4)Inter-frequency OP 1 to neighbouring cells <maxCellMeas> >Frequency infoMD Frequency info 10.3.6.36 >CHOICE mode MP >> FDD >>>Primary CPICH infoOP Primary CPICH info 10.3.6.60 >>> Common SIB MP 1 to info<maxCommSIB> >>>>Common SIB MP Enumerated(SIB1, indicator SIB2, SIB5, .. .) >>>>Value tag MD Integer (1 . . . 4) >>TDD >>>Primary CCPCH info MPPrimary CCPCH info 10.3.6.57 >>> Common SIB MP 1 to info<maxCommSIB> >>>>Common SIB MP Enumerated(SIB1, indicator SIB2, SIB5, .. .) >>>>Value tag MD Integer (1 . . . 4)A second format of the new SIB type including a specific common SIB1value tag is provided below.

Information Type and Element/Group name Need Multi referenceIntra-frequency OP 1 to neighbouring cells <maxCellMeas> >CHOICE modeMP >> FDD >>>Primary CPICH info OP Primary CPICH info 10.3.6.60 >>>Common SIB MP 1 to info <maxCommSIB> >>>>Common SIB MP Enumerated(SIB2,indicator SIB5, . . .) >>>>Value tag MD Integer (1 . . . 4) >>> SIB1Value tag OP Integer (1 . . . 256) >>TDD >>>Primary CCPCH info MPPrimary CCPCH info 10.3.6.57 >>> Common SIB MP 1 to info<maxCommSIB> >>>>Common SIB MP Enumerated(SIB2, indicator SIB5, . ..) >>>>Value tag MD Integer (1 . . . 4) >>> SIB1 Value tag OP Integer (1. . . 256) Inter-frequency OP 1 to neighbouring cells<maxCellMeas> >Frequency info MD Frequency info 10.3.6.36 >CHOICE modeMP >> FDD >>>Primary CPICH info OP Primary CPICH info 10.3.6.60 >>>Common SIB MP 1 to info <maxCommSIB> >>>>Common SIB MP Enumerated(SIB2,indicator SIB5, . . .) >>>>Value tag MD Integer (1 . . . 4) >>> SIB1Value tag OP Integer (1 . . . 256) >>TDD >>>Primary CCPCH info MPPrimary CCPCH info 10.3.6.57 >>> Common SIB MP 1 to info<maxCommSIB> >>>>Common SIB MP Enumerated(SIB2, indicator SIB5. . ..) >>>>Value tag MD Integer (1 . . . 4) >>> SIB1 Value tag OP Integer (1. . . 256)

The new SIB type can include a first section for intra-frequencyneighbouring cells and a second section for intra-frequency neighbouringcells, where the maximum number of neighbouring cells is specified bythe parameter maxCellMeas.

Communications between an RNC and a UE can be according to a frequencydivision duplex (FDD) mode or a time division duplex (TDD) mode. In theintra-frequency neighbouring cells section of the new SIB type, if themode of communication is FDD, then the Common SIB info IE can beincluded with the Primary CPICH info group, which provides informationpertaining to the common pilot channel (CPICH). On the other hand, ifthe communication mode is the TDD mode, then the Common SIB info IE isincluded with the Primary CCPCH info information group, which includesinformation pertaining to the common control physical channel (CCPCH).The primary CPICH info IE and the Primary CCPCH info IE are according tocurrent standards are described in 3GPP TS 25.331. They identify thecell to which Common SIB info IE relates.

The inter-frequency section of the new SIB type also can be similarlydivided into two subsections for FDD mode and TDD mode communications.

In some cases, the SIB type(s) common between a serving cell and aneighbouring cell may be the same for all neighbouring cells. Instead ofsignaling such common SIB type(s) separately using multiple instances ofthe Common SIB info IE, as discussed above, in some alternativeimplementations, the Common SIB info IE can have optional IEs. In suchexamples, the first Common SIB info IE in a list includes both theCommon SIB indicator and the value tag, as discussed above. However,subsequent Common SIB info IEs can omit the common SIB indicator andvalue tag, and each such subsequent Common SIB info IE implies that theIEs associated with the previous Common SIB info IE in the list areused.

For example, consider a list of eight neighbouring cells, where the listincludes eight Common SIB info IEs for the respective eight neighbouringcells. The list can include eight instances of the New intra-frequencycells information group in the Intra-frequency cell info listinformation group discussed further above. Assume that the Common SIBinfo IE for the first neighbouring cell has a Common SIB indicator ofSIB1 and value tag of 1, and the Common SIB info IE for the fifthneighbouring cell has a Common SIB indicator of SIB2 and value tag of 3.Also assume that the Common SIB info IEs for the second, fourth, andsixth cells in the list do not have the respective Common SIB indicatorand value tag IEs. In this example, the Common SIB indicator and valuetag IEs of the Common SIB info IE specified for the first neighbouringcell would apply to the first, second, and fourth cells, and the CommonSIB indicator and value tag IEs of the Common SIB info IE specified forthe fifth neighbouring cell would apply to the fifth and sixth cells.

To implement the foregoing, the Common SIB info IE can be modified asfollows, where the Common SIB indicator and value tag IEs are optionalelements:

> Common SIB CV- 1 to info BCH <maxCommSIB> >>Common SIB MDEnumerated(SIB1, indicator SIB2, SIB5, . . .) >>Value tag MD Integer (1. . . 4)A second format of the Common SIB info IE including an SIB1 value tag isprovided below:

> Common SIB CV- 1 to info BCH <maxCommSIB> >>Common SIB MDEnumerated(SIB2, indicator SIB5, . . .) >>Value tag MD Integer (1 . . .4) >Common SIB1 CV- Enumerated (TRUE) indicator BCH >> SIB1 Value tag MDInteger (1 . . . 256)

Alternatively, an optional Common SIB info For All Intra Frequency CellsIE can be added that applies to all neighbouring cells or neighbouringcells of a certain type, such as all intra-frequency neighbours orinter-frequency neighbours. The example modified intra-frequencymeasurement system information group can be as follows:

Information Type and Element/Group name Need Multi referenceIntra-frequency MD Measurement measurement identity identity 10.3.7.48Common SIB CV- 1 to info For All BCH <maxCommSIB> Intra FrequencyCells >>Common SIB MP Enumerated(SIB1, indicator SIB2, SIB5, . ..) >>Value tag OP Integer (1 . . . 4) <Other IEs not affected by thischange are not shown here>A second format of the modified intra-frequency measurement systeminformation group including an SIB1 value tag is provided below:

Information Type and Element/Group name Need Multi referenceIntra-frequency MD Measurement measurement identity identity 10.3.7.48Common SIB CV- 1 to info For All BCH <maxCommSIB> Intra FrequencyCells >>Common SIB MP Enumerated(SIB2, indicator SIB5, . . .) >>Valuetag OP Integer (1 . . . 4) SIB1 Value tag CV- Integer (1 . . . 256) BCH<Other IEs not affected by this change are not shown here>

It is noted that the alternative signaling options discussed with thetwo tables above can also be applied to other solutions, such asSolutions 2-4 discussed below.

Solution 1 can be used to send the area scope extending indicator to aUE that is in idle mode. An idle mode UE does not have an RRC connectionwith an RNC. In addition, Solution 1 can be used to send the area scopeextending indicator to a UE that is in certain connected modes (wherethe UE has established an RRC connection with an RNC). For example, suchconnected modes include the following modes as described by 3GPP TS25.331: CELL_FACH (forward access channel); CELL_PCH (cell pagingchannel); and URA_PCH (UTRAN routing area paging channel). In otherexamples, other types of connected modes can be used.

Solution 2

In accordance with alternative implementations, referred to as Solution2, the area scope extending indicator can be included in a dedicatedmessage, instead of a broadcast message as used for Solution 1. Solution2 can be employed for a UE in certain connected modes, which is a UEthat has a radio connection with an RNC that can be used to communicatedata. Such connected modes can include the following modes as describedby 3GPP TS 25.331: CELL_DCH (dedicated channel); and CELL_FACH. In otherexamples, other connected modes can be used.

As shown in FIG. 2, the UE performs a connection establishment procedure(202) with a source RNC of a source cell (a cell currently serving theUE), for establishing a connection. In some examples, the connectionestablishment procedure can be a Radio Resource Control (RRC) connectionestablishment procedure for establishing an RRC connection.

As part of the connection establishment procedure (202), the UE can send(at 204) a UE capability indicator, including a Support of common SIBreuse indicator to the RNC, to indicate that the UE is capable ofreusing common system information that is common among multiple cells(or other extended area). In response to the Support of common SIBreuse, the RNC sends (at 206) a dedicated message to the UE thatcontains an area scope extending indicator, for identifying theneighbouring cell(s) and SIB type(s) that is common between the sourcecell and the neighbouring cell(s).

The Support of common SIB reuse indicator can be included in an RRCCONNECTION SETUP COMPLETE message, and more specifically, in a UE radioaccess capability information group of the foregoing message. Forexample, the common SIB reuse capability indicator can be a new IE addedto the UE radio access capability information group as set forth below(the remaining IEs are described in 3GPP TS 25.331, and will not bediscussed further):

Information Type and Element/Group name Need Multi reference Accessstratum release MP Enumerated(R99) indicator CV- Enumerated(REL-4,not_rrc_connec- REL-5, tionSetupComplete REL-6, REL-7, REL-8, REL-9,REL-10, REL-11) DL capability with CV- Enumerated(32 simultaneous HS-not_iRAT_HoInfo kbps, 64 kbps, DSCH configuration 128 kbps, 384 kbps)PDCP capability MP PDCP capability 10.3.3.24 RLC capability MP RLCcapability 10.3.3.34 Transport channel MP Transport channel capabilitycapability 10.3.3.40 <Partly omitted> Support of common OP Enumerated(TRUE) SIB reuse UE based network CV- UE based network performancenot_iRAT_HoInfo performance measurements measurements parametersparameters 10.3.3.53 Support ofUTRAN CV- Enumerated (TRUE) ANRnot_iRAT_HoInfo IMS Voice capability CV- IMS Voice not_iRAT_HoInfocapability 10.3.3.14b Multiflow capability CV- UE Multiflownot_iRAT_HoInfo capability 10.3.3.21ba Support of MAC-ehs OP Enumerated(TRUE) window size extension Support of UM RLC CV- Enumerated (TRUE)re-establishment not_iRAT_HoInfo via reconfiguration

The absence of the common SIB reuse capability IE indicates that the UEdoes not support common system information reuse.

If both the UE and the RNC support common SIB reuse, then the RNC sendsthe area scope extending indicator in a dedicated message (at 206). Thededicated message can be a new message or an existing message. If usingan existing message, the existing message can be a Measurement Controlmessage, which can include an Intra-frequency cell info list informationgroup as set forth below:

Information Type and Element/Group name Need Multi reference CHOICEIntra-frequency cell OP removal >Remove all intra-frequencycells >Remove some intra-frequency cells >>Removed intra-frequency cellsMP 1 to <maxCellMeas> >>>Intra-frequency cell id MP Integer(0 . . .<maxCellMeas> - 1) >Remove no intra-frequency cells New intra-frequencycells OP 1 to <maxCellMeas> >Intra-frequency cell id OP Integer(0 . . .<maxCellMeas> - 1) >Cell info MP Cell info 10.3.7.2 > Common SIB OP 1 toinfo <maxCommSIB> >>Common SIB MP Enumerated(SIB1, indicator SIB2, SIB5,. . .) >>Value tag OP Integer (1 . . . 4) >CHOICE mode specific infoMP >>No information >>TDD 1.28 Mcps >>> SNPL Monitor Set Indicator OPBit string(5) Cells for measurement CV- 1 to BCHopt<maxCellMeas> >Intra-frequency cell id MP Integer(0 . . . <maxCellMeas>-1) CSG Intrafrequency cell info CV- 10.3.7.121 BCHopt Intra-frequencySI Acquisition CV- 10.3.7.125 BCHoptA second format of an Intra-frequency cell info list information groupincluding a specific SIB1 value tag is provided below.

Information Type and Element/Group name Need Multi reference CHOICEIntra-frequency cell OP removal >Remove all intra-frequencycells >Remove some intra-frequency cells >>Removed intra-frequency cellsMP 1 to <maxCellMeas> >>>Intra-frequency cell id MP Integer(0 . . .<maxCellMeas> - 1) >Remove no intra-frequency cells New intra-frequencycells OP 1 to <maxCellMeas> >Intra-frequency cell id OP Integer(0 . . .<maxCellMeas> - 1) >Cell info MP Cell info 10.3.7.2 > Common SIB OP 1 toinfo <maxCommSIB> >>Common SIB MP Enumerated(SIB2, indicator SIB5, . ..) >>Value tag OP Integer (1 . . . 4) >SIB1 value tag OP Integer (1 . .. 256) >CHOICE mode specific info MP >>No information >>TDD 1.28Mcps >>> SNPL Monitor Set Indicator OP Bit string(5) Cells formeasurement CV- 1 to BCHopt <maxCellMeas> >Intra-frequency cell id MPInteger(0 . . . <maxCellMeas> -1) CSG Intrafrequency cell info CV-10.3.7.121 BCHopt Intra-frequency SI Acquisition CV- 10.3.7.125 BCHopt

The Intra-frequency cell info list information group includes a CommonSIB info IE, similar to that described above in connection with Solution1.

A new dedicated message can have the following format, which is similarto the format of the new SIB type for Solution 1 discussed above:

Information Type and Element/Group name Need Multi referenceIntra-frequency OP 1 to neighbouring <maxCellMeas> cells >Cell IdentityOP Cell Identity 10.3.2.2 >CHOICE mode MP >> FDD >>>Primary CPICH infoOP Primary CPICH info 10.3.6.60 >>> Common SIB OP 1 to info<maxCommSIB> >>>>Common SIB MP Enumerated(SIB1, indicator SIB2, SIB5, .. .) >>>> Value tag OP Integer (1 . . . 4) >>TDD >>>Primary CCPCH infoMP Primary CCPCH info 10.3.6.57 >>> Common SIB OP 1 to info<maxCommSIB> >>>> Common SIB MP Enumerated(SIB1, indicator SIB2, SIB5, .. .) >>>> Value tag OP Integer (1 . . . 4) Inter-frequency OP 1 toneighbouring <maxCellMeas> cells >Cell Identity OP Cell Identity10.3.2.2 >CHOICE mode MP >> FDD >>>Primary CPICH info OP Primary CPICHinfo 10.3.6.60 >>> Common SIB OP 1 to info <maxCommSIB> >>>> Common SIBMP Enumerated(SIB1, indicator SIB2, SIB5, . . .) >>>> Value tag OPInteger (1 . . . 4) >>TDD >>>Primary CCPCH info MP Primary CCPCH info10.3.6.57 >>> Common SIB OP 1 to info <maxCommSIB> >>>> Common SIB MPEnumerated(SIB1, indicator SIB2, SIB5, . . .) >>>> Value tag OP Integer(1 . . . 4)A second format of the new dedicated message including a specific SIB1value tag is provided below.

Information Type and Element/Group name Need Multi referenceIntra-frequency OP 1 to neighbouring <maxCellMeas> cells >Cell IdentityOP Cell Identity 10.3.2.2 >CHOICE mode MP >> FDD >>>Primary CPICH infoOP Primary CPICH info 10.3.6.60 >>> Common SIB OP 1 to info<maxCommSIB> >>>>Common SIB MP Enumerated(SIB2, indicator SIB5, . ..) >>>> Value tag OP Integer (1 . . . 4) >>> SIB1 value tag OP Integer(1 . . . 256) >>TDD >>>Primary CCPCH info MP Primary CCPCH info10.3.6.57 >>> Common SIB OP 1 to info <maxCommSIB> >>>> Common SIB MPEnumerated(SIB2, indicator SIB5, . . .) >>>> Value tag OP Integer (1 . .. 4) >>> SIB1 value tag OP Integer (1 . . . 256) Inter-frequency OP 1 toneighbouring <maxCellMeas> cells >Cell Identity OP Cell Identity10.3.2.2 >CHOICE mode MP >>FDD >>>Primary CPICH info OP Primary CPICHinfo 10.3.6.60 >>> Common SIB OP 1 to info <maxCommSIB> >>>> Common SIBMP Enumerated(SIB1, indicator SIB2, SIB5, . . .) >>>> Value tag OPInteger (1 . . . 4) >>> SIB1 value tag OP Integer (1 . . .256) >>TDD >>>Primary CCPCH info MP Primary CCPCH info 10.3.6.57 >>>Common SIB OP 1 to info <maxCommSIB> >>>> Common SIB MP Enumerated(SIB1,indicator SIB2, SIB5, . . .) >>>> Value tag OP Integer (1 . . . 4) >>>SIB1 value tag OP Integer (1 . . . 256)

Alternatively, the content of the table above can be included in anotherexisting message, instead of being in a new message.

Solution 3

The foregoing describes solutions that either employ a broadcast message(Solution 1) or a dedicated message (Solution 2) to send the area scopeextending indicator. In alternative implementations, referred to asSolution 3, Solutions 1 and 2 can be combined, to allow an RNC toselectively use a broadcast message or a dedicated message tocommunicate the area scope extending indicator to a UE. Note that theRNC can also send the area scope extending indicators in both abroadcast message and a dedicated message.

FIG. 3 is a flow diagram of an example process according to someimplementations. As depicted in FIG. 3, the RNC selects (at 302) one ofmultiple techniques to send the area scope extending indicator. Themultiple techniques can include a technique according to Solution 1, atechnique according to Solution 2, or a technique according to combinedSolutions 1 and 2. The selection of the technique to use can be based onthe mode that the UE is in, such as idle mode or certain connectedmodes. If a target UE is in an idle mode or certain specified connectedmodes (e.g. CELL_FACH, CELL_PCH, URA_PCH), then the RNC can selectSolution 1 to send a broadcast message containing the area scopeextending indicator. If the target UE is in other connected modes (e.g.CELL_DCH, CELL_FACH), then the RNC can select Solution 2 to send adedicated message containing the area scope extending indicator. If theRNC is to send the area scope extending indicator to multiple UEs thatare in different modes, then the RNC can send the area scope extendingindicator in both broadcast and dedicated messages.

The RNC then sends (at 304) the area scope extending indicator using theselected technique.

Solution 4

The foregoing describes examples where the RNC sends the area scopeextending indicator to a UE. Alternatively, the area scope extendingindicator can be sent from one UE to another UE, assuming that the UEsare in physical proximity to each other such that a direct wireless linkcan be established between the UEs. As examples, the UEs can be in thesame building, in the same room, in the same car, and so forth. UEs thatare in physical proximity to each other are likely to be camped on thesame cell and/or have the same neighbouring cells.

The wireless link between the UEs can include a Bluetooth link, a WiFilink (e.g. a WiFi Direct link), a near-field communication (NFC) link,an infrared link, a device-to-device (D2D) link, or other link.

A first UE can send the full system information (read by the first UEfrom an RNC) to a second UE. Alternatively, or additionally, the firstUE can send the area scope extending indicator to the second UE, whichidentifies certain system information that is common between multiplecells. The system information of a mobile communications network can beexchanged as part of user plane data or as part of control signaling inthe wireless link between the UEs.

In a scenario where the UEs are camped on the same cell, it is likelythat one of the UEs (the first UE) reselected and camped on the cellearlier than the other UE (the second UE). As a result, the first UEknows if and which of the system information between the source andtarget cells is common as a result of the reselection process. Thisknowledge regarding common system information between the source andtarget cells can be sent by the first UE to the second UE over ashort-range wireless communication, such as over any of the wirelesslinks noted above.

In some examples, the area scope extending indicator can be sent by thefirst UE to the second UE prior to the second UE reselecting to the sametarget cell. As a result, the second UE can be informed in advancebefore reselecting to the target cell that certain system information iscommon between the source cell and target cell. In this way, the secondUE can avoid re-reading the common system information, which savesresources of the second UE.

In a scenario where both UEs are camped on two different neighbouringcells (which may be a temporary situation in practice), it is possiblethat the UEs can exchange full system information directly using ashort-range communication. For this latter solution to work, anassumption can be made that the short range direct communication costfor the UEs (e.g. in terms of energy consumption or communicationlatency) due to the exchange of common system information is lower thanreading the common system information from the RNC. This can be the casewhere the radio interface communication between the RNC and UEs is lessenergy efficient and slower than the short range communication betweenUEs.

FIG. 4 is a flow diagram of an example process that involves UE1, UE2,RNC A (in cell A), and RNC B (in cell B). In the FIG. 4 example, it isassumed that both UE1 and UE2 are initially camped on cell A (at 402).System information A is broadcast (at 404) from RNC A, which is receivedby UE1 and UE2.

Next, it is assumed that UE1 reselects to and camps on cell B (at 406).After the reselection, RNC B of cell B broadcast (at 408) systeminformation B, which is received by UE1.

Once UE1 has received system information B, UE1 can identify (at 410)certain system information (e.g. certain SIB type(s) and/or certainSB(s)) that is (are) common between cell A and cell B. This identifyingcan be based on comparing system information A to system information Bby UE1.

Once the common system information is identified by UE1, UE1 sends (at412) an area scope extending indicator (similar in format to any of theindicators discussed above in connection with Solutions 1 and 2) to UE2.

Subsequently, UE2 reselects to and camps on cell B (at 414). After thereselection by UE2, RNC B broadcasts (at 416) system information B. UE2would not have to re-read the common system information (in systeminformation B) that was indicated by the area scope extending indicatorsent by UE1, unless the respective value tag(s) indicate(s) that thecommon system information has been updated.

RNC Functionality

FIG. 5 is a flow diagram illustrating tasks performed by wireless accessnetwork entities (or more simply, “network entities”) (Entity A andEntity B are shown in the example of FIG. 5), in accordance with someimplementations. Entity A and Entity B can be separate RNCs that controlrespective different cells. Alternatively, Entity A and Entity B can beentities within a common RNC that controls different cells. In thelatter example, Entity A and Entity B can be separate modules executableon the common RNC. The network entities exchange (at 502) systeminformation configuration information, which describes the configurationof the system information of each cell. The system informationconfiguration can describe the configuration of SIB types and of SBs.

Based on the system information configuration received from Entity B,Entity A is able to identify (at 504) the system information that iscommon between Entity A and Entity B. Similarly, based on the systeminformation configuration received from Entity A, Entity B is able toidentify (at 506) the system information that is common between Entity Aand Entity B.

Although FIG. 5 depicts the tasks involving just two network entities,it is noted that more than two network entities can be involved, suchthat each network entity can identify common system information of morethan two network entities.

Once the common system information is identified by each network entity,the network entities can send (at 508, 510) respective area scopeextending indicators to corresponding UEs served by the networkentities.

System Architecture

FIG. 6 is a block diagram of an example system that includes a UE 602and a wireless access network node 604 (e.g. combination of an RNC andNodeB, or some other type of wireless access network node). The UE 602includes system information read logic 606, which can includemachine-readable instructions executable on one or more processors 608.A processor can include a microprocessor, microcontroller, processormodule or subsystem, programmable integrated circuit, programmable gatearray, or another control or computing device.

The processor(s) 608 can be coupled to a network interface 610 and astorage medium (or storage media) 612. The network interface 610 allowsthe UE 602 to wirelessly communicate with the wireless access networknode 604.

The storage medium (or storage media) 612 can store information 614 ofan area scope extending indicator that was received through the networkinterface 610 from the wireless access network node 604. The systeminformation read logic 606 can use the stored information 614 of thearea scope extending indicator to identify common system informationthat does not have to be re-read by the UE 602.

The wireless access network node 604 includes common system informationdetermination logic 616 and area scope extending indicator logic 618,which can both be implemented as machine-readable instructionsexecutable on one or more processors 620. The common system informationdetermination logic 616 is able to identify common system informationshared with other wireless access network node(s). A description of suchcommon system information (626) can be stored in a storage medium (orstorage media) 624 that is coupled to the processor(s) 620.

The processor(s) 620 can also be coupled to a network interface 622 toallow the wireless access network node 604 to communicate wirelesslywith the UE 602.

The area scope extending indicator logic 618 is able to generate an areascope extending indicator that is to be sent to the UE 602, either in abroadcast message or dedicated message, or both.

Data and instructions are stored in respective storage devices, whichare implemented as one or more computer-readable or machine-readablestorage media (e.g. 612 and 624). The storage media include differentforms of memory including semiconductor memory devices such as dynamicor static random access memories (DRAMs or SRAMs), erasable andprogrammable read-only memories (EPROMs), electrically erasable andprogrammable read-only memories (EEPROMs) and flash memories; magneticdisks such as fixed, floppy and removable disks; other magnetic mediaincluding tape; optical media such as compact disks (CDs) or digitalvideo disks (DVDs); or other types of storage devices. Note that theinstructions discussed above can be provided on one computer-readable ormachine-readable storage medium, or alternatively, can be provided onmultiple computer-readable or machine-readable storage media distributedin a large system having possibly plural nodes. Such computer-readableor machine-readable storage medium or media is (are) considered to bepart of an article (or article of manufacture). An article or article ofmanufacture can refer to any manufactured single component or multiplecomponents. The storage medium or media can be located either in themachine running the machine-readable instructions, or located at aremote site from which machine-readable instructions can be downloadedover a network for execution.

In the foregoing description, numerous details are set forth to providean understanding of the subject disclosed herein. However,implementations may be practiced without some or all of these details.Other implementations may include modifications and variations from thedetails discussed above. It is intended that the appended claims coversuch modifications and variations.

What is claimed is:
 1. A method comprising: sending, by a wirelessaccess network node to a user equipment (UE), an indicator that extendsan area scope of system information.
 2. The method of claim 1, whereinthe system information includes one or more selected from among a systeminformation block and a scheduling block.
 3. The method of claim 1,wherein the indicator identifies one or more selected from among asystem information block and a scheduling block that is shared by one ormore neighbouring cells.
 4. The method of claim 1, wherein the systeminformation is interpretable by the UE as having a cell scope withoutthe indicator, and wherein the indicator extends the area scope of thesystem information to multiple cells.
 5. The method of claim 1, whereinthe indicator further includes a value tag associated with the systeminformation, the value tag useable to determine whether the systeminformation has been updated.
 6. The method of claim 1, wherein sendingthe indicator comprises sending the indicator in a broadcast message. 7.The method of claim 6, wherein sending the indicator in the broadcastmessage comprises sending the indicator in an information element in asystem information block.
 8. The method of claim 6, wherein sending theindicator in the broadcast message comprises sending the indicator in anew system information block.
 9. The method of claim 1, wherein sendingthe indicator comprises sending the indicator in a dedicated message.10. The method of claim 9, further comprising: receiving, by thewireless access network node, a capability indication from the UEindicating that the UE supports an ability to reuse common systeminformation of two or more cells.
 11. The method of claim 1, whereinsending the indicator comprises selectively sending the indicator in oneof a broadcast message and a dedicated message.
 12. The method of claim11, further comprising: selecting, by the wireless access network node,the broadcast message to send the indicator for the UE that is in one ofan idle mode and at least a subset of connected modes.
 13. The method ofclaim 11, further comprising: selecting, by the wireless access networknode, the dedicated message to send the information for a UE that is inone of a subset of connected modes.
 14. A user equipment (UE)comprising: at least one processor configured to: receive an indicatorthat extends an area scope of system information received by the UE, thesystem information transmitted by a first cell.
 15. The UE of claim 14,wherein the indicator is to be received from a wireless access networknode of the first cell.
 16. The UE of claim 14, wherein the indicator isto be received from another UE.
 17. The UE of claim 14, wherein the atleast one processor is configured to further: reselect to a second cellthat transmits further system information.
 18. The UE of claim 14,wherein the at least one processor is configured to further: reselect toa second cell that transmits further system information; determine, froma value tag specified in the indicator, whether the system informationidentified by the indicator has been updated in the further systeminformation; in response to determining that the system informationidentified by the indicator has not been updated, avoid re-reading thesystem information identified by the indicator from the further systeminformation; and in response to determining that the system informationidentified by the indicator has been updated, re-reading the systeminformation identified by the indicator from the further systeminformation.
 19. The UE of claim 14, wherein the at least one processoris configured to further: reselect to a second cell that transmitsfurther system information; identify common system informationtransmitted by the first and second cells; and send a further indicatorto another UE, the further indicator extending an area scope of theidentified common system information.
 20. The UE of claim 14, whereinthe at least one processor is configured to further receive the systeminformation from another UE.
 21. A method comprising: receiving, by afirst wireless access network entity from a second wireless accessnetwork entity, a system information configuration of the secondwireless access network entity; identifying, by the first wirelessaccess network entity based on the received system informationconfiguration, common system information between the first and secondwireless access network entities; and sending, by the first wirelessaccess network entity to a user equipment (UE), an indicator extendingan area scope of the common system information.